1. Field of the Invention
The present invention relates to a substrate processing apparatus for performing a series of processings including a heat treatment and a chemical processing on a thin substrate (hereinafter simply referred to as "substrate") such as a semiconductor wafer or a liquid crystal glass substrate.
2. Description of the Background Art
A substrate processing apparatus is employed for performing various processings on a substrate such as a semiconductor wafer or a glass substrate for a liquid crystal display unit, a photomask or an optical disk. In a fabrication process for a semiconductor device, for example, employed is a substrate processing apparatus prepared by unifying a series of processings and integrating a plurality of processing units with each other for improving production efficiency.
FIG. 12 is a perspective view showing an exemplary conventional substrate processing apparatus. The substrate processing apparatus shown in FIG. 12 has processing areas A and B and a transport area C.
The processing area A is provided with rotary coating units (spin coaters) SC for coating substrates W with a processing solution and a rotary developing unit (spin developer) SD for supplying a developing solution to the substrates W for developing the same in parallel with each other. The processing area B is provided with a plurality of stages of heating units (hot plates) HP for heat-treating (thermal processing) the substrates W and cooling units (cool plates) CP for cooling the substrates W. The transport area C is provided with a transport unit 5 for transporting the substrates W.
A take-in/take-out unit (indexer) 6 for storing the substrates W and taking in/out the same is provided along single ends of the processing areas A and B and the transport area C. The indexer 6 comprises a plurality of cassettes 61 for storing the substrates W and a transfer robot 62 for taking in/out the substrates W. The transfer robot 62 of the indexer 6 moves along arrow U for taking out the substrates W from the cassettes 61, transferring the same to the transport unit 5, receiving the substrates W subjected to the series of processings from the transport unit 5 and returning the same to the cassettes 61.
The transport unit transports the substrate W along arrow S in the transport area C, introduces and discharges the substrates W into and from the aforementioned processing units, and transfers and receives the substrates W to and from the transfer robot 62.
In the aforementioned conventional substrate processing apparatus, a plurality of processing units having different types of functions are planarly arranged while processing units having the same type of functions are vertically arranged in a plurality of st ages.
In recent years, the diameters of substrates are increased for improving producibility, and the dimensions of respective processing units are also increased in response thereto. Thus, a substrate processing apparatus formed by integrating a plurality of processing units with each other is also increased in size, to result in increase of its footprint (area planarly occupied by the substrate processing apparatus). Therefore, there is a need for a substrate processing apparatus which can effectively utilize a space in clean room.
On the other hand, it is important to control atmospheres for substrate processings. Therefore, the aforementioned substrate processing apparatus is generally installed in the clean environment of a clean room or the like. In particular, a chemical processing unit such as the aforementioned spin coater SC or spin developer SD, for example, must be strictly atmosphere-controlled, since not only the cleanliness of the atmosphere but the temperature and humidity thereof exert remarkable influence on the results of the processing.
In general, therefore, a chemical processing unit is supplied with air which is adjusted and controlled in temperature and humidity by a temperature and humidity control unit provided in the exterior of the apparatus. Such a temperature and humidity control unit is installed in a space separated from the apparatus body or set to cover the overall upper surface of the apparatus.
However, the aforementioned temperature and humidity control unit requires an installation space therefor, and hence the footprint of the overall substrate processing system is increased to hinder efficient utilization of the clean room.
Further, the temperature and humidity control unit is set in the exterior of the apparatus, and hence the air adjusted in temperature and humidity must be guided to the apparatus through a duct. This duct also requires a space therefor, and hence the footprint of the overall substrate processing system is further increased. In addition, thermal energy loss is caused by heat radiation from the duct or heat absorption from the exterior of the duct, to cause difficulty in temperature control of the air in the chemical processing part.